The U.S. Supreme Court today dismissed a class-action lawsuit involving up to 1.5 million women who sued Wal-Mart for gender discrimination, citing the work of three University of Virginia law professors who have criticized the empirical methodology behind the plaintiffs’ argument.

In a 5-4 decision delivered by Justice Antonin Scalia, the court ruled in Dukes v. Wal-Mart that the class action should not have been certified based on “commonality,” the degree to which the class of plaintiffs had enough in common to form a “class.” There was no companywide evaluation system that applied to all employees, he said, and no proof that Wal-Mart operated under a general policy of discrimination, the justices said.

“The only evidence of a ‘general policy of discrimination’ respondents produced was the testimony of Dr. William Bielby, their sociological expert,” Scalia wrote in the opinion.

Bielby examined Wal-Mart’s employee policies and concluded that the company used personnel practices that were biased against female employees and led to disparities in pay and promotion between men and women.

Bielby testified using “social framework” analysis, a practice defined through the work of University of Virginia law professors John Monahan and Larry Walker, in which the use of general social science evidence provides background information or context that may assist the judge or jury when evaluating case-specific evidence.

However, the framers of social framework analysis took issue with the manner in which Bielby applied it to the Wal-Mart case.

“I’m happy that a majority of the court focused on commonality and agreed with our analysis that the only evidence offered by the plaintiffs on that point was the testimony of Dr. Bielby,” Walker said. “They rejected his testimony.”

The majority opinion cites a Virginia Law Review article by Monahan, Walker and law professor Greg Mitchell criticizing Bielby’s testimony for not studying Wal-Mart’s employment practices through accepted social science research methods.

“The Bielby testimony, just as we proposed, was at the heart of the result,” Walker said. “Our horse in this race is simply to treat the scientific evidence correctly. Our contention is that Dr. Bielby did not use an appropriate methodology.”

The dissenting justices disagreed with the majority for using the commonality standard as a basis for dismissing the case and wanted to remand the case back to the 9th Circuit.